Continuous fuel injection



Nwv. 1947. F. J. WIEGAND Er AL CONTINUOUS FUEL INJECTION Filed Feb. 23,1944 {NVENTO b.

Patented Nov. 4, 1947 CONTINUOUS FUEL INJECTION Francis J. Wiegand.Ridgewood, William T. Stark, Paterson, and Mark Robert Rowe, Teaneck, N.J., assignors to Wright Aeronautical Corporation, a corporation of NewYork Application February 23, 1944, Serial No. 523,770

15 Claims. (Cl. 123-119) 1 This invention relates to fuel distributingsystems and is particularly directed to a fuel distributing system foran engine.

In a multi-cylinder internal combustion engine it is necessary toproperly control the fuel supp and its ratio to the air supply and todistribute the fuel and air equally between the variousengine cylinders.In a carburetion type internal combustion engine the total flow of fuelis regulated in proportion to the'airfiow and is continuously dischargedinto the air intake duct of the engine induction system from whence thefuel-air mixture is distributed to the various engine cylinders throughtheir respective intake pipes. In such a system the drop in temperatureproduced by the vaporization ofthe fuel upon discharge into theinduction system may produce icing conditions therein, and in addition,if the fuel and air is not uniformly mixed, the fuel will not beuniformly distributed to the various engine cylinders. In lieu of suchcarburetion systems, internal combustion engines are also equipped withso-called fuel injection systems in which the fuel is individually andintermittently injected into each cylinder, thereby positivelyproportioning the fuel between the various engine cylinders. However,such intermittent fuel injection systems are complicated by thenecessity of providing pump means in combination with selective valvemechanism for feeding and distributing the fuel to the variouscylinders.

It is' an object of this invention to provide a continuous fuelinjection system which provides means for proportioning the fuel betweenthe individual engine cylinders. It is a further object of thisinvention to provide means for controlling the total fuel flow incombination with means for continuously discharging the fuel throughindividual discharge nozzles associated withthe engine cylinders. It isa further object of the invention to deliver the total regulated fuelsupply to a reservoir connected to individual fuel discharge valves,each adapted to continuously discharge fuel into the intake pipe for anengine cylinder.

, In an aircraft engine the relative elevation of the various enginecylinders will vary with changes in the attitude of the aircraft, andtherefore, it is a further object of this invention to 'providemeans tomake the rate of fuel delivery of each discharge valveindependent ofchanges in the relative elevation of the various engine cylinders andtheir associated fuel discharge valves.

Other objects of the invention will become apparent upon reading theannexed detailed de- 2 scription in connection with the drawing inwhich:

Figs. 1 and 2 are schematic rear end and side views, respectively,illustrating the invention applied to a radial cylinder internalcombustion engine, and i Fig. 3 is a detailed section view of one of thedischarge nozzles.

Referring to the drawing, a conventional radial cylinder aircraft engineI0 is provided with radially disposed cylinders it having intake andexhaust valves l2 and I3, respectively. A carburetor or other fuelmetering device I4, to which fuel is supplied under pressure, issupported on the engine or section Iii. -A carburetor adapter or conduitsection l8 establishes communication between the carburetor and theintake of a conventional engine driven supercharger 20, which in turndischarges the combustion air into an annular' manifold 22 from whenceit is distributed to the various engine cylinders through their intakepipes 24. The structure so far described is quite conventional.

The fuel metering device it may comprise any suitable mechanism to whichfuel is supplied under pressure and in which the fuel is metered anddelivered under pressure, for example, in accordance with the total airflow as in the fuel metering device disclosed in Patent No. 2,165,447 toK. Browne. The metered fuel is delivered to a fuel reservoir or fueldistributing manifold 26 which,

24 is provided with a fuel discharge valve or nozzle 28 having its inletside connected to the fuel distributing manifold through a conduit 30,The fuel pressure communicated from the manifold 2-6 through conduits 30to each discharge valve, urges each valve in an opening directionagainst a suitable spring or other balancing force. If the engine werealways to'remain in a substantially constant attitude, the springbiasing force for urging each of the valves in a closing direction couldbe adjusted to compensate for the differ encein fuel pressur at eachvalve resulting from their differencein elevation; That is, with theengine remaining in a substantially constant attitude each valve 28 maybe adjusted such that fuel is always discharged at the same rate intoeach of the intake pipes 24. Upon an increase or a decrease in theamount of fuel supplied to the manifold 26, each valve 28 will open orclose to discharge fuel at a corresponding larger or smaller rate intoits associated intake pipe.

With such an arrangement and with the engine maintained in a constantattitude, fuel is continuously discharged into each of the intake pipesat equal rates. the fuel being picked up by the air supply to eachintake pipe and taken into the associated cylinders on their intakestrokes. However, in operation, particularly in an aircraft engineinstallation, the relative elevation of the various fuel dischargevalves will be continuously changing, and therefore, it is essentialthat such changes in relative elevation of the various valves have noeffect or have the same efiect on each valve in order to maintain theproper division of fuel flow through the valves.

To this end each fuel valve and the entire fuel system is designed sothat fuel is admitted to both sides of the valve operating means in sucha manner that the differential fuel pressure acting on each valveoperating means is the same regardless Of the relative elevation ofthese valves. With such a system the fuel discharge valves may beadjusted to properly divide the fuel flow regardless of the attitude ofthe engine.

Referring particularly to Fig. 3, each valve 28 comprises a housing oftwo halves 32 and 34 between which a diaphragm 36 is supported, Amovable valve member 38 is secured to the diaphragm 36 by a nut 40 andis slidably received within an annular valve guide 42. The valve guide42 is threaded within the housing part 32 and clamps a nozzle member 44thereto. A conventional spiral type nozzle plug 46 is secured within thenozzle 44 and is provided with a plurality of helically disposed grooves48 about its periphery. The housing part 32 has an inlet opening 50 forthe conduit 30, whereby fuel is admitted therefrom to the interior ofthe housing and against the valve side of the diaphragm 38. The annularvalve guide 42 is provided with one or more circumferentially spacedopenings 52 and the valve member has a tapered end 54 cooperatingtherewith. For clarity this taper has been greatly magnified in thedrawing. With this construction upon axial movement of the valve member38, the junction 55 of its tapered end 54 with the remainder of thevalve member moves across the openings 52 to control the extent to whichthe valve is open.

The valve housing part 34 is provided with an adjusting sleeve 55threaded therein and an axially disposed adjusted screw 58 is threadedthrough one end of said sleeve. The screw 58 is provided with a head end60 having a, helical groove 52 about its periphery for receiving one endof a helically coiled spring 84. The other end of the spring 64 engagesthe nut 40 to urge the valve member 38 in a closing direction againstthe fuel pressure acting on the valve side of the diaphragm 38. Upon anincrease in the fuel supplied to the fuel manifold 26, there will be anincrease in the. fuel pressure therein and at the inlet side of each ofthe valves, whereby this increased fuel pressure acts against the valveside of each. valve operatin diaphragm 36 to effect a further openin ateach of the valves to maintain a proper division of the fuel flow. Anyadjustment of the screw 58 relative to the sleeve 56 threads the helicalgroove 62 of the head 60 along the spring, thereby controlling thelength and stiffness of thespring. Also, adjustment of the sleeve 56determines the fuel pressure at which the valve member 38 begins toopen. In order that the sleeve 56 may be adjusted without disturbing theadjustment of the spring 64, the threads on the exterior of theadlusting sleeve 55 may be right handed and its internal threadscooperating with the screw 58 may be left handed, but of the same pitch.A lock nut 36 and a cap 68 are threaded about the sleeve 55 asillustrated.

In addition to the action of the springs 64, each of the valves 38 isalso urged in a closing direction by a fuel pressure admitted to thehousing portion 34 and against the rear side of the diaphragm 36 throughan inlet opening 10. The housing portion of each valve 34 is alsoprovided with an outlet opening 12, and conduits 14 interconnect theexit opening I2 of one valve housing with the inlet opening of anothervalve housing to serially connect the chambers at the rear sides of thediaphragms 35. As illustrated in Fig. l,

the housing parts 34 of the fuel discharge valves for cylinders on theone side of the engine are serially connected together, and similarly,the valve housing parts 34 associated with the cylinders on the otherside of the engine are serially connected together. Also, the lower endsof the fuel manifold 26 are connected to the inlet openings of the valvehousing portions 34 for the lower end cylinders of eachseries throughrestricted orifices I6 and conduits 18. The outlet openings 12 'of thevalve housing portions 34 for the upper end cylinders of each series areconnected through conduits to a valve 82 discharging into the carburetoradapter. The valve 82 is a common type valve which is spring biasedtoward closed position and is urged toward open position in response tothe fuel pressure supplied thereto. The valve 82 is designed to maintaina small back pressure in order to insure that the conduits l4, l8 and 80and housings 34 remain full of fuel. Because of the small size of therestricted orifices 16, the magnitude and the range of the back pressuremaintained by the valve 82 is much smaller than the magnitude and therange of the fuel pressure within the manifold 26. For example, the fueldischarge pressure at each discharge valve may vary from nine to elevenpounds per square inch between their closed and full open of thediaphragm 36 balances the force of the spring 64 and the fuel pressureon the other side of the diaphragm. Upon an increase or a decrease intheamount of fuel supplied to the fuel distributing manifold 26 therewill be a similar opening or closing adjustment of each fuel dischargevalve to maintain a proper division of fuel flow. Also, the fuelpressure on the valve side of any two diaphragms 36 differs only by anamount dependent on the difference in the fuel head at each diaphragm,which depends only on the difference in elevation of the two diaphragms.Similarly, the difference in the fuel pressure on the rear side of anytwo diaphragms differs only by an amount dependent on the difference inthe fuel head at each diaphragm, which difference also depends only onthe difference in elevation of the two diaphragms.- That is, if any onediaphragm 3B is at a higher elevation than a second diaphragm, the fuelpressure on both sides of the one diaphragm will be greater than thecorresponding fuel pressures on the two sides of the In other words, thefuel pressure differential on each diaphragm 36 is the same regardlessof their relative elevation and therefore the extent to which each valveopening 52 is uncovered is always the same and the fuel flow througheach valve is substantially the same. Actually, although each valveopening 52 is uncovered to the same extent, the pressure differentialacross these openings will be slightly larger for the lower valvesbecause of the larger static fuel head on their inlet sides. However,this latter variation in pressure differential has substantially noefiect on the relative magnitude of the fuel flow through each valve,particularly as compared to the effect on fuel flow which acorresponding variation in pressure diiferential across the diaphragms36 would have because of the resulting variation in the extent to whicheach valve opening 52 would be uncovered. In fact, each valve 28obviously may be so designed that the fuel pressure differential betweenits inlet and outlet sides is such at each valve opening that the flowthrough the valve depends primarily only on the extent to which thevalve opening 52 is uncovered.

While we have described our invention in detail in its present preferredembodiment, it will be obvious to those skilled in the art, afterunderstanding our invention, that various changes and modifications maybe made therein without departing from the spirit or scope thereof. Weaim in the appended claims to cover all such modifications and changes.

We claim as our invention:

1. In an internal combustion engine comprising a plurality of cylinderseach with an intake passage and an intake valve therefor, a fuel systemcomprisin a plurality of fuel discharge valves each respectivelyassociated with one of the engine cylinders, means toregulate the totalfuel flow and to feed said fuel to said valves, each of said valvesbeing adapted to continuously discharge fuel into the intake passage ofits associated cylinder anterior of the intake valve .of said cylinder,and means to automatically adjust said valves to properly divide thefuel between the engine cylinders independently of changes in theirrelative elevation.

2. In an internal combustion engine having a plurality of cylinders eachwith an intake pipe: a fuel system comprising means to regulate thetotal fuel flow, and to feed said fuel under pressure to a fueldistributing manifold, a plurality of fuel discharge valve eachrespectively associated with one of said intake pipes, each of saidvalves having its inlet side connected to said manifold and beingadapted to continuously discharge fuel therefrom into its associatedintake pipe, means to adjust each of said valves automatically inresponse to change in the fuel pressure supplied thereto, and means torender each of said valve adjusting means independent of the relativeelevation of said valves.

3. In an internal combustion engine having a plurality of cylinders eachwith an air intake pipe, a fuel system comprising a fuel distributingmanifold means for regulating the total fuel flow and feeding said fuelunder pressure to said fuel manifold, a fuel discharge valve for eachintake pipe, each of said valves having its inlet side connected to saidfuel manifold and being adapted to continuously discharge fuel therefrominto its associated'intake pipe, valve operating means for 6 each ofsaid valves, each or said valve operating means having one sideresponsive to the pressure of the fuel supplied to the inlet side of itsassociated valve for urging said valve in an opening direction, liquidpassage means interconnecting the opposed sides of said valve operatingmeans, and means for maintaining said liquid passage means full of fuel.

4. In an internal combustion engine having a plurality of cylinders, anair intake duct, and an air intake pipe for each of said cylindersconnected to said intake duct; a fuel system comprising a fueldistributing manifold, means for regulating the total fuel flow andfeeding said fuel under pressure to said manifold, a fuel dischargevalve for each cylinder intake pipe, each of said valves having itsinlet side connected to said fuel manifold and being adapted tocontinuously discharge fuel therefrom into its associated intake pipes,a fuel chamber associated with each of said valves, said chambers beingconnected in series with one end of said series of chambers connected tosaid fuel manifold through a restricted orifice, the other end of saidserially connected chambers being arranged to discharge fuel flowingtherethrough into said intake duct, and valve operating means for saidvalves, each of said valve operating means being responsive to the fuelpressure supplied to the inlet side of its associated valve for urgingsaid valve in an opening direction and to the fuel pressure within thechamber associated with said valve for ur ing said valve in a closingdirection.

5. A fuel system for an engine comprising a fuel manifold, means to feedfuel under pressure to said manifold, a plurality of spaced fueldischarge valves each having their inlet sides in communication withsaid manifold, means for adjusting each of said valves, each saidadjusting means having one side in communication with the fuel suppliedto its associated valve for urging said valve in an opening direction,fuel passage means interconnecting the opposed sides of each of saidvalve adjusting means; and means for maintaining fuel under pressurewithin said passage means for urging each of said valves in a closingdirection.

6. In an engine having a fuel distributing manifold and a plurality ofspaced fuel discharge valves in communication therewith; the method ofcontrolling the fuel flow to said engine comprising the steps ofsupplying fuel under pressure to said manifold, continuously dischargingfuel fromsaid manifold through said valves during engine operation,adjusting each of said valves in response to changes in the fuelpressure of said manifold, and rendering the extent to which each valveopens or closes independent of changes in the relative elevation of saidvalves.

7. In an engine having a plurality of cylinders each with an individualintake passage, a fuel distributing manifold and a plurality 'of fueldischarge valves, each communicating with said manifold and respectivelyadapted to discharge fuel into one of said intake passages; the methodof controlling the fuel flow comprising the steps of supplying fuelunder pressure to said manifold,

continuously discharging fuel from said manifold through said valvesduring engine operation, adjusting each of said valves in responsetochanges in the fuel pressure in said manifold, and rendering theextent to which each valve opens or closes independent of changes in therelative elevation of said valves.

8. In an internal combustion engine having a plurality of cylinders, aplurality of fuel discharge valves, one for each cylinder, each of saidvalves being arranged to continuously discharge fuel during engineoperation, a plurality of means each respectively connected to one ofsaid valves and operative to adjust its associated valve with changes inthe'pressure of the: fuel supplied thereto, and means for automaticallyrendering each said valve adjusting means ineffective to adjust itsassociated valve in response to changes in the pressure of the fuelsupplied thereto as a result of changes in the relative elevation ofsaid valves- 9. In an internal combustion engine having a plurality ofcylinders each having an intake pipe, a fuel distributing manifold,means to supply fuel under pressure to said manifold, a plurality offuel discharge valves each respectively adapted to continuouslydischarge fuel from said manifold into one of said intake pipes duringengine operation, a plurality of means each respectively connected toone of said valves and operative to adjust its associated valve withchanges in the pressure of the fuel supplied thereto, and means forautomatically rendering each said valve adjusting means ineffective toadjust its associated valve in response to changes in the pressure ofthe fuel supplied thereto as a result of changes in the relativeelevation of said valves.

10. A fuel system for an engine comprising a fuel distributing manifold,means to supply fuel under pressure to said manifold, a plurality ofspaced fuel discharge valves having their inlet sides in communicationwith said manifold, each of said valves being arranged to continuouslysupply fuel tosaid engine during engine operation,

fuel manifold, means to supply fuel under pressure to said manifold, aplurality of spaced fuel discharge valves, each of said valves havingtheir inlet sides in communication with said manifold, a plurality ofmeans each respectively connected to one of said valves and normallyoperative to automatically adjust its associated valve with changes inthe pressure of the fuel supplied thereand means to automatically adjustsaid valves to maintain a predetermined-division of the fuel betweensaid valves independently of changes in their relative elevation.

11. A fuel system for an engine comprising a plurality of spaced fueldischarge nozzles each adapted during engine operation to continuouslysupply fuel thereto, and means operative to control each of said nozzlessuch that the fuel flow through each nozzle is substantially independentof changes in the relative elevation of said nozzles.

2. A fuel system for an engine comprising a fuel distributing manifold,a plurality of spaced fuel dischargevalves each adapted during engineoperation to continuously supply fuel thereto from said manifold, andmeans operative to adjust each of said valves in response to changes inthe fuel pressure at their inlet sides except as to fuel pressurechanges at their inlet sides resulting from changes in the relativeelevation of said valves.

13. 'A fuel system for an engine comprising a to, and means forautomatically rendering each said valve adjusting means ineflective toadjust its associated valve in response to changes in fuel pressuresupplied thereto as a result of changes in the relative elevation ofsaid valves.

14., A fuel system for an engine comprising a fuel manifold, means tosupply fuel under pressure to said manifold, a plurality of spaced fueldischarge valves each of said valves having their inlet sides incommunication with said manifold, and'means operative to control theposition of each of said valves such that the fuel flow through eachvalve is continuous during engine operation and is substantiallyindependent of changes in the relative elevation of said valves.

15. A fuel system for an engine, said system comprising a plurality ofspaced fuel discharge valves each adapted to continuously supply fuel tosaid engine during engine operation, interconnected fuel passages forsupplying fuel to said valves, a plurality of means each connected toone of said valves for automatically adjusting said valves such that thefuel iiow therethrough is independent of changes in their relativeelevation, each of said valve adjusting means being subjected on oneside to the pressure of the fuel supplied to the inlet side of its valvefor urging its valve in one direction, and fuel passage meansinterconnecting the opposite sides of said valve adjusting means suchthat the fuel pressure on said opposite sides of the valve adjustingmeans urges their respective valves in the opposite direction.

FRANCIS J. WIEGAND.

WILLIAM T. STARK.

MARK ROBERT ROWE.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS

